[MRI imaging of purulent cerebral ventriculitis]

This report concerns a 68-year-old male who was diagnosed as having purulent ventriculitis based on CT and MRI findings. He was first admitted to a nearby hospital with fever and impaired consciousness and thought to be suffering from herpes simplex encephalitis based on laboratory findings. In spite of treatment with acyclovir and antibiotics, his symptoms persisted for one and a half months. Because of gradual deterioration of his neurological status, he was transferred to our hospital. On admission he was stuporous with nuchal rigidity and a fever of 38.5 degrees C. The CSF leukocyte count was elevated (217/mm3) with predominantly polymorphonuclear cells (mononuclear 20, polymorphonuclear 197). Gd-DTPA MRI (T1-weighted) showed marked enhancement of the ependyma of the fourth ventricle and both lateral ventricles. A diagnosis of purulent ventriculitis was made and high-dose antibiotics (ABPC 12g, CTX 9g) were started intravenously. Gradual improvement in the clinical signs was observed with rapid normalization of the CSF cell-count. The patient had completely recovered one month after the start of treatment and this was associated with disappearance of abnormal enhancement on the MRI images. Although cerebral ventriculitis occasionally occurs as a complication of neonatal meningitis, it is rare in adult purulent meningitis. In our patient, persistent meningitis combined with impaired drainage of CSF from the ventricles are presumed to have caused ventriculitis. Serial enhanced MRI is particularly helpful in diagnosing ventriculitis, and can serve as a good index for monitoring the effects of treatment.